#include
#include
#include
int main() {
std::ifstream file("data.txt");
std::string line, numStr;
// read first line
std::getline(file, line);
// read first value of first line
std::istringstream lineStream(line);
std::getline(lineStream, numStr, '\t');
std::cout
Подробнее здесь: [url]https://stackoverflow.com/questions/79172473/read-double-value-from-a-file-stdinvalid-argument-after-stdstod-call[/url]